1. Field of the Invention
The present invention relates to the fabrication of molded plastic electric outlet boxes, and relates more specifically to an improved electric outlet enclosure of the type having a plurality of components one of which is a universal base for receiving boxes of different depth. The box is configured to receive a snap-on face plate. The molded plastic box is also adapted to receive a conventional electric devices such as duplex plugs or switches with simplified push-in fastener openings that do not require threading the fasteners in place.
2. Description of the Prior Art
Plastic frames for the mounting of interchangeable electrical devices are known in the art. For example, U.S. Pat. No. 3,964,705 illustrates a molded one piece frame having resilient integrally molded posts that flex outwardly to receive electrical devices to be mounted in the frame. The '705 patent does not show or suggest an enclosure defined by a base and a snap-on box for housing an electrical component and that permits one of a plurality of boxes to be used on a single universal frame or base.
U.S. Pat. No. 3,689,868 illustrates a snap-on face plate which defines a cord enclosure in conjunction with another enclosure component. Cooperating posts are defined in part both on the face plate and on the other component. However, the '868 patent disclosure does not relate to a multicomponent enclosure for mounting an electrical device or duplex plug. This patent merely shows a fixed frame around which an electrical cord can be wound. In this '868 patent there is no suggestion for a base plate adapted to receive a molded box suitable for housing a duplex plug or switch.
U.S. Pat. No. 4,500,746 shows a self-contained electrical device that is designed to eliminate the need for a molded plastic outlet box altogether. The electric device, such as a switch, is received on a base that is in turn provided with wires that are so located as to engage contacts provided in the switch. The switch is designed to be assembled with a base by means of resilient upstanding posts that latch into appropriate openings defined for them in the frame or base.
U.S. Pat. No. 4,857,669 shows a plurality of integrally molded posts 42, each of which has a notched end 44 adapted to receive a projecting portion of an electrical component to be assembled therewith. This patent like the above mentioned prior art patents merely shows that it is old to provide resilient posts with latches adapted to be received in openings provided for this purposes in another component to be assembled therewith.
U.S. Pat. Nos. 5,170,013 and 5,170,014 disclose an electrical outlet box with molded plastic end walls defining threaded fastener openings adapted to receive a fastener by simply pushing the fastener into the opening. The fastener openings have integrally formed threads provided in the molded plastic so once the fastener has been pushed into place removal requires that the fastener be unthreaded. The subject application shows for the first time how a push in fastener can be used with a molded plastic outlet box without the need for threads being formed in the plastic itself. In the structure disclosed herein greater resilient flexibility is provided for the plastic fastener hole defining portion. Each such portion defines a hole which is tapered in cross-sectional size from an enlarged entry end into a necked-down star-shaped inner-end.
U.S. Pat. No. 4,983,785 shows a molded plastic outlet box having end walls that define three outwardly open slots, the middle slot having an enlarged hole for receiving a fastener equal in length to the axial extent of the hole. This fastener hole has a threaded outer or upper axial end portion and a reduced diameter inner portion that requires self tapping by rotation of the threaded fastener. In the present invention the fastener hole need not be threaded, nor is it defined by outwardly open slots.